Lubricant for photographic film



United States ddzlfih Patented Feb. 11,- 1964 No Drawing. Filed June 6,1960, Ser. No. 33,905 12 Claims. (Cl. 252--56) This invention relates tothe lubrication of film. More particularly this invention concerns thelubrication of photographic film in its unexposed form.

It is well known in the industry that the Winding, withdrawing, passingof film through magazines and film gates and the like may be facilitatedby the application of a lubricant to the film. A number of filmlubricant compositions have already been suggested in the prior art.Many of such prior art lubricants are largely comprised of commercialWaxes. More recently certain lauric acid compounds have been suggestedfor film lubrication purposes and have obtained substantial usage. Suchlauric acid materials appear to lubricate film better than thecommercial Waxes. However, lauric acid is reactive with certain gelatinsof high isoelectric point, making it difficult to coat uniformly and insome cases leaving a haze in the gelatin layer. Lauric acid materialsalso tend to reduce the quality of certain color films, making itundesirable to use from the photographic standpoint.

In the lubrication of photographic film products many of the prior artlubricating materials have not been entirely satisfactory. There is theproblem that the lubricants adversely afiect the sensitive emulsioncarried on the photographic film product. Some of the prior art fattyacid type lubricants may tend to streak the film surface which isdetrimental to the quality of the photographic product. A large numberof the prior art lubricants are not reasonably permanent in theirlubricating effect on the film. That is, such lubricants become removedfrom the photographic film to a substantial extent during the passing ofthe film through photographic baths for the processing thereof. Otherproblems may be encountered such as undesirable interaction of thelubricant with other coatings or constituents contained in thephotographic film.

Accordingly it is believed apparent that the develop ment of improvedlubricants for film products represents a highly desirable result. Afterextended investigation I have found a lubricant and methods for usethereof which are thought to overcome or minimize many of thedifiiculties encountered in the industry with prior art types oflubricants.

This invention has for one object to provide an improved filmlubricating composition. Another object is to provide a lubricatedunexposed photographic film which exhibitsa minimum of friction whenpassed through film magazine, film gates and the like. Still anotherobject is to pro vide a film lubricating composition which will impartmore permanent lubrication to film products than prior art lubricants.Other objects will appear hereinafter.

In the broader aspects of my invention I have found that certain waxyesters of higher fatty alcohols and higher fatty acids, typified bymodified sperm oils, make execellent lubricants for this purpose and inaddition, possess several advantages over prior art film lubricants asexemplified by lauric acid. In further detail a preferred material,having the greatest number of desirable characteristics, is Spermafol52. This material is a waxy solid, characterized as a partiallyhydrogenated sperm oil, with a low level (7%) of unsaturation and amelting point in the range of 47-5 1 C. Spermafol 52 consists of amixture of esters, varying between C and C chain length for the acidportion and between C and C chain length for the alcohol portion,largely C to Ci straight chain fatty acids and'-C -to'-C straight chainfatty alcohols, together with a portion of saturated triglycerides. Atypical component ester present in large concentration might be cetylpalmitate, CH (CH COO(CH CH In practice, the modified sperm oil isdispersed in a photographic gelatin coating medium, then coated over aphotographic emulsion, either black-and-White or color, to form aprotective, lubricating top coat. Besides gelatin the dispersing agentmay be some other colloidal material such as colloidal albumin, acellulose derivative, or a synthetic resin, for instance, a polyvinylcompound. Some colloids which may be used are polyvinyl alcohol or ahydrolyzed polyvinyl acetate as described in Lowe US. Patent 2,286,215,issued June 16, 1952; a far hydrolyzed cellulose ester such as celluloseacetate hydrolyzed to an acetyl content of 19-26% as described in US.Patent 2,327,808, of Lowe and Clark, issued August 24, 1943; awater-soluble ethanolamine cellulose acetate as described in Yutzy US.Patent 2,322,085, issued June 15, 1943; a polyacrylamide or an imidizedpolyacrylamide as described in Lowe, Minsk, and Kenyon U.S. Patent2,541,474, issued February 13, 1951; zein as described in Lowe US.Patent 2,563,791, issued August 7, 1951; a vinyl alcohol polymercontaining urethane carboxylic acid groups of the type described inUnruh and Smith US. Patent 2,768,154, issued October 23, 1956; orcontaining cyano-acetyl groups such as the vinyl alcohol-vinylcyanoacetate copolymer as described in Unruh, Smith, and Priest U.S.Patent 2,808,331, issued October 1, 1957; or a polymeric material whichresults from polymerizing a protein or a saturated acylated protein witha monomer having a vinyl group as described in US. Patent 2,852,382, ofIllingsworth, Dann, and Gates, issued September 16, 1958; or certainacrylate copolymers may be used such as the copolymers described inHouck et 211. Serial No. 786,227, now US. Patent 3,062,674.

If desired, compatible mixtures of two or more of these colloids may beemployed for dispersing the lubricant in its preparation.

Although the aforementioned sperm oil product obtainable commercially asSpermafol 52 is preferred, there are several other sperm oil productswhich may be used such as follows:

Spermafol 45 Sperm oil 38 B/W Sperm oil 45 N/W Liquid Cosmol Cosmol 1000Spermaceti wax These are all esters of higher fatty alcohols and higherfatty acids, essentially similar in structure but varying in averagemolecular weight, degree of unsaturation and triglyceride content. Eachof these possesses some merit as film lubricants.

All of the sperm oil products referred to above are commerciallyavailable materials available from the Archer-Daniels-Midlands Company.

Synthetically prepared waxy esters of alcohols and acids, each componentbeing a straight-chain aliphatic compound of 10 to 20 carbon atoms havebeen found to be as satisfactory a lubricant as the modified naturallyoccurring sperm oils.

Accordingly, it appears sufficient herein to generically identify thesesperm oil products used in the present invention as being essentiallycomprised of esters of higher fatty alcohols and higher fatty acids of amolecular weight within the range of about 300 to about 600, and havinga degree of unsaturation within the range of 2% to A modified sperm oil,as above described, may be compounded into a lubricating composition bya method as set forth below. This method illustrates the compounding ofthe preferred sperm oil product identified as Sperrnafol 52. However,the other waxy esters may be compounded into lubricating compounds ofthe present invention in a generally similar manner. A mixture of thefollowing composition is prepared:

EXAMPLE I ADM Spermafol 52 g 30 photographic gelatin g 384 16% saponinsolution "cc..- 40

The Spermafol was heated above its melting point, to about 60 C., thenpoured, with vigorous stinring, into the saponin-gelatin solution heldat about 4050 C. This mixture was dispersed in a colloid mill, formingSpermafol particles of colloidal dimensions, up to about 3 micronsdiameter. The mill was rinsed with 25 cc. warm water and the dispersiondiluted with 808 grams 10% gelatin. To make up a compositon containingthe above dispersion for coating on a photographic product, thefollowing two examples demonstrate the method and material.

EXAMPLE II To 0.2 lb. of the melted dispersion are added:

30 cc. of a saponin solution 4156 g. of a 10% photographic gelatin 1.2g. of mucochloric acid in a 2.5% water solution Enough water to make upto a total weight of 14.0 lbs.

EXAMPLE III To 2.0 lbs. of the melted dispersion are added:

240 cc. of a 15% saponin solution 4156 g. of a 10% photographic solution1.2 g. of mucochloric acid and in a 2.5% Water solution Enough water tomake up a total of 66 lbs.

Additional examples showing the use of hydrophilic colloids other thangelatin are as follows:

EXAMPLE IV To: 50 cc. 5% aqueous polyvinyl alcohol (Elvanol 52-22) Add 1cc. 10% sodium lauryl sulfate (Stepanol ME); 10

cc. sperm oil (ADM 38 N.W. Sperm) 2.5 grams of a medium viscosity gradeof polyvinyl alcohol, about 88% hydrolyzed, was dissolved by stirringinto 47.5 cc. of cold water containing the sodium lauryl sulfate. Thesperm oil was added with vigorous stirring and the resulting coarsedispersion passed through a colloid mill to give a stable suspension ofcolloidally dispersed droplets of sperm oil in the polymer solution.

EXAMPLE V Four grams of a copolymer of ethyl acrylate (80 parts) andacrylic acid parts) were swollen in a mixture of 7.5 grams ofisopropanol and 75 cc. of water. While stirring, sufiicient ammoniumhydroxide was added to dissolve the polymer and being the pH to 6.3. Thesolution was then adjusted to 100 grams with additional water.

To 50 cc. of this solution there was added 1 cc. of 10% sodium laurylsulfate solution, followed by 10 cc. of sperm oil, as in Example IV. Avery good colloidal disperson resulted.

EXAMPLE VI Ten grams of zein were dissolved in 90 cc. of 50% aqueousisopropanol. One cc. of 10% aqueous Triton X-lOO was added, and 4 gramsof sperm oil were stirred in with vigorous agitation to form a gooddispersion.

EXAMPLE VII 70 cc. of a latex formed by the emulsion polymerization of15' parts acrylonitrile, 85 parts of vinylidene chloride and 8 parts ofacrylic acid and containing 15% l polymer solids by weight, were treatedwith ammonium hydroxide (7% N3 to form a viscous clouded solution atabout pH 7.5. To this dope were added 4 grams of sperm oil and themixture was stirred for about 10 minutes at room temperature to form astable dispersion.

EXAMPLE VIII Ten grams of a high viscosity grade of polyacrylamide(American Cyanamid were dissolved by stirring into 400 cc. of coldwater. To 50 cc. of this viscous solution were added 2 grams of spermoil. After a few minutes stirring, a good dispersion resulted.

EXAMPLE IX 2.5% Union Carbide Cellosize WP 40, hydroxyethyl cellulose,was prepared as in Example VIII and 2 grams sperm oil stirred into 50cc. of this solution to give a stable dispersion.

EXAMPLE X A 2% by weight solution of polyethylene oxide resin (UnionCarbide Polyox Willi-205) was prepared by stirring 10 g. of this polymerinto 500 cc. of water and 2 grams of sperm oil stirred into 50 cc. ofpolymer to give a good dispersion.

EXAMPLE XI To 50 cc. of 5% aqueous photographic gelatin, add:

5.0 cc. of a 15% saponin solution 3.0 g. of cetyl palmitate The oilymelted ester was added with vigorous stirring and the resulting coarsedispersion is passed through a colloid mill as in Example IV.

EXAMPLE XII The dispersion was made exactly like Example XI except that3.0 g. of the ester of dodecyl alcohol and stearic acid were used inplace of cetyl palmitate.

While I have favored the formula which dispersed the lubricant in thegelatin with saponin, a somewhat coarser dispersion may be satisfactorysuch as would be obtained by omitting the saponin. If a finer dispersionis desired, to achieve a less hazy layer for example, this can beaccomplished by using other surfactants.

The approximate range of particle sizes that would contain most of theparticles obtained under these conditions is as follows:

Microns (1) No surfactant 1-5 (2) Surfactant 0.2-3

Note that Examples VII through X are prepared without added surfactant,the resin having suflicient dispersing activity to make a (relatively)stable colloidal dispersion. Other surfactants may be incorporated asdesired in specific applications as is disclosed hereinafter.

The dispersion may contain a lauryl or oleyl monoether of polyethyleneglycol as described in Knox and Davis U.S. Patent 2,831,766, issuedApril 22, 1958; a salt of a sulfated and alkylated polyethylene glycolether as described in Knox and Davis U.S. Patent 2,719,087, issuedSeptember 27, 1955; an acylated alkyl taurine such as the sodium salt ofN-oleyl-N-methyl taurine as described in Knox, Twardokus, and Davis U.S.Patent 2,739,891, issued March 27, 1956; the reaction product of adianhydride of tetracarboxy-butane with an alcohol or an aliphatic aminecontaining from 8 to 18 carbon atoms which is treated with a base, forexample, the sodium salt of the monoester of tetracarboxybutane asdescribed in Knox, Stenberg, and Wilson U.S. Patent 2,843,487, issuedJuly 15, 1958; a water-soluble maleopimarate as described in Knox andFowler U.S. Patent 2,823,123, issued February 11, 1958; an alkali metalsalt of a substituted amino acid as disodium N-(carbo-p-tert.octylphenoxypentaethoxy)-glutamate as described in Knox and Wilson U.S.patent application Serial No. 600,679, filed July 30, 1956, now U.S.Patent 3,038,804; or sulfosuccinamate such as tetrasodiumN-(1,2-dicarboxyethyl)-N-octadecy1 sulfosuccinamate as described in Knoxand Stenberg U.S. patent application 691,125, filed October 21, 1957,now U.S. Patent 2,992,108, or a sodium salt of an alkylarylpolyethersulfonate of Baldsiesen U.S. Patent 2,600,831, issued June 17, 1952.

The inclusion of mucochloric acid in Examples II and III is for thepurpose of after-hardening the coated gelatin layers. Such gelatinhardener may be replaced in part or entirely by other chemicals such asformaldehyde; or salts of chromium (III) or aluminum (III); or acompound having a plurality of acid anhydride groups such as7,8-diphenylbicyclo-(2,2,2)-7-octene-2,3,5,6-tetracarboxylicdianhydride, or a dicarboxylic or a disulfonic acid chloride such asterephthaloyl chloride as described in Allen and Carroll U.S. Patents2,725,294 and 2,725,- 295, both issued November 29, 1955; a cyclic1,2-diketone such as cyclopentane-1,2-dione as described in Allen andByers U.S. Patent 2,725,305, issued November 29, 1955; a bisester ofmethanesulfonic acid such as 1,2-di-(methane-sulfonoxy)-ethane asdescribed in Allen and Laakso U.S. Patent 2,726,162, issued December 6,1955; 1,3-dihydroxymethylbenzimidazol-2-one as described in July, Knott,and Pollalk U.S. Patent 2,732,316, issued January 24, 1956; a dialdehydeor a sodium bisulfite derivative thereof such as ,B-methylglutaraldehyde bis-sodium bisulfite as described in Allen and BurnessU.S. patent application Serial No. 556,031, filed December 29, 1955, nowabandoned; a bis-aziridine carboxamide such as trimethylenebis(1-aziridine carboxamide) as described in Allen and Webster U.S.patent application Serial No. 599,891, filed July 25, 1956, now U.S.Patent 2,950,197; 2,3-dihydroxy dioxane as described in Jeffreys U.S.Patent 2,870,013, issued January 20, 1959; or bis-isocyanate asdescribed in Henn et al. U.S. patent application Serial No. 805,357,filed April 10, 1959.

After preparing the lubrication composition of the present invention bythe aforesaid procedure, said composition may be applied by standardemulsion coating techniques to the photographic film product which it isdesired to lubricate.

The gel-lubricant mixture is usually coated in a thin layer of about /2to 1; in thickness. Or, in diiferent terms, the gel is coated at about0.100 gm./ft. and the lubricant at about 0.0005 to 0.010 gm./ft.Although the lubricant would generally be applied over the emulsionsurface of the film product, the lubricating composition of the presentinvention may be applied over a surface of the film opposite theemulsion surface, on both sides of the film or in layers within amultilayer structure.

The excellent lubricating effect of the lubricant of the presentinvention may be ascertained by any suitable test method. The recentlyissued U.S. Patent 2,882,157 to my associates described several caseswhere it may be desirable to reduce the friction on film by thelubricating of the film and such patent describes the tests which may beused, the conducting of such tests under certain relative humidityconditions and the like details.

One test not described in the aforementioned patent is the emulsion digsusceptibility test. This is conducted as follows: On the regular teston raw film two pieces of film are placed emulsion down beneath aweighted ball bearing. The top piece of film is then pulled from beneaththe bearing, the bottom piece of film being held stationary. The ratingis the minimum weight required to produce visible damage to the filmwhen processed and examined under normal viewing conditions.

On processed film the test is made more severe by placing the filmemulsion side up beneath the bearing and examining the surface. By thismethod only a range of digging susceptibility is determined. I

In the present invention for the purposes of comparison I have testedthe lubricating effect of the new composition of the present inventionin accordance with the foregoing test procedures and the results are asfollows:

Testing to show the greater permanence of the lubricant of the presentinvention may be readily noted by comparison of photomicrographs ofsurface characteristics. 'Film lubricated by the present invention showsthe same lubricant pattern on film which has passed through an entirecolor process (color developer, bleach, fix, washes), whereas filmlubricated in accordance with the prior art (as a lauric acid lubricantafter such a lubricated film has been through several comparable baths)shows the lubricant does not survive processing.

While in the above examples I have described the use of my preferredcomposition prepared from the sperm oil product Spermafol 52,satisfactory results may be obtained by using other of the modifiedsperm oil or synthetic materials referred to above. For example using alubricating composition comprised of hydrophilic colloid, mucochloricacid and the wetting agents identified above but containing in place ofSpermafol another sperm oil product such as spermaceti wax, results asfollows were obtained:

Caefiicient 0f Fricti0n-Metal to Emulsion Spermaceti wax in protectivecoat 0.11 Spermafol 52 in protective coat 0.11 Lauric acid in protectivecoat 0.20 Control, no lubricant in protective coat 0.44

as described hereinabove and as defined in the appended claims.

I claim:

1. A lubricating composition for photographic film products, saidcomposition consisting essentially of a hydrophilic photographic-typecolloid and /2 to 15% by weight of the colloid of modified sperm oilessentially consisting of esters of higher fatty alcohols and higherfatty acids of a molecular weight within the range of about 300 to about600, and having a degree of unsaturation within the range of 2% to 75%,wherein the alcohols and acids each have straight chain lengths from 10to 20 carbon atoms.

2. A lubricating composition for photographic film products, saidcomposition consisting essentially of a hydrophilic photographic-typecolloid and /2 to 15% by weight of the colloid of modified sperm oilessentially about 360 to about 600, and having a degree of unsaturationwithin the range of 2% to 75%, wherein the alcohols and acids each havestraight chm'n lengths from to 20 carbon atoms, and a surfactantcompatible with photographic silver halide emulsions which aids inimproving the spreading properties of the lubricant.

3. A lubricating composition for photographic film products, saidcomposition consisting essentially of a hydrophilic colloid selectedfrom the class consisting of gelatin, polyvinyl alcohol, a copolymer ofethyl acrylate and acrylic acid, zein, an interpolymer of acrylonitrile,vinylidene chloride and acrylic acid, polyacrylamide, hydroxyethylcellulose, and polyethylene oxide resin, and A to by weight of thecolloid, of modified sperm oil essentially consisting of esters ofhigher fatty alcohols and higher fatty acids of a molecular weightwithin the range of about 300 to about 600, and having a degree ofunsaturation within the range of 2% to 75%, wherein the alcohols andacids each have straight chain lengths from 10 to carbon atoms.

4. A lubricating composition for photographic film products, saidcomposition consisting essentially of a hydrophilic colloid selectedfrom the class consisting of gelatin, polyvinyl alcohol, a copolymer ofethyl acrylate and acrylic acid, Zein, an interpolymer of acrylonitrile,vinylidene chloride and acrylic acid, polyacrylamide, hydroxyethylcellulose, and polyethylene oxide resin, a surfactant compatible withsilver halide photographic emulsions which aids in improving thespreading properties, and /2 to 15% by weight of the colloid of modifiedsperm oil essentially consisting of esters of higher fatty alcohols andhigher fatty acids of a molecular weight within the range of about 300to about 600, and having a degree of unsaturation within the range of 2%to 75%, wherein the alcohols and acids each have straight chain lengthsfrom 10 to 20 carbon atoms.

5. The composition of claim 3 in which the hydrophilic colloid isgelatin.

6. The composition of claim 3 in which the hydrophilic colloid ispolyvinyl alcohol.

7. A method of preparing a lubricating composition indicated in claim 1,which comprises heating the waxy ester above its melting point, addingthe melted waxy ester to an agitated aqueous solution of a hydrophilicphotographic-type colloid, the amount of waxy ester being about /2% to15 by weight based on the colloid, and adding to the resultingcomposition a surfactant whereby the particle size of the melted waxyester is reduced.

8. A method in accordance with claim 7 in which the hydrophilic colloidis polyvinyl alcohol.

9. A method in accordance with claim 7 in which the hydrophilic colloidis gelatin.

10. A method in accordance with claim 7 in which the hydrophilic colloidis a copolymer of ethyl acrylate and acrylic acid.

11. A method of lubricating photographic film which comprises applyingto the emulsion layer a layer of a composition consisting essentially ofa hydrophilic photographic-type colloid having dispersed therein /2 to15% by weight of a modified sperm oil consisting essentially of estersof higher fatty alcohols and higher fatty acids of a molecular weightwithin the range of about 300 to about 600 and having a degree ofunsaturation within the range of 2% to in which the alcohols and acidseach have straight chain lengths from 10 to 20 carbon atoms.

12. A method of claim 11 wherein the hydrophilic colloid is gelatin.

References Cited in the file of this patent UNITED STATES PATENTS1,883,913 Hickman Oct. 25, 1932 OTHER REFERENCES Hydrofol Products,copyright 1954 by Archer- Daniels-Midland Co. (Chemical ProductsDivision), 2191 West th Street, Cleveland 2, Ohio; 40 pages.

1. A LUBRICATING COMPOSITION FOR PHOTOGRAPHIC FILM PRODUCTS, SAIDCOMPOSITION CONSISTING ESSENTIALLY OF A HYDROPHILIC PHOTOGRAPHIC-TYPECOLLOID AND 1/2 TO 15% BY WEIGHT OF THE COLLOID OF MODIFIED SPERM OILESSENTIALLY CONSISTING OF ESTERS OF HIGHER FATTY ALCOHOLS AND HIGHERFATTY ACIDS OF A MOLECULAR WEIGHT WITHIN THE RANGE OF ABOUT 300 TO ABOUT600, AND HAVING A DEGREE OF UNSATURATION WITHIN THE RANGE OF 2% TO 75%,WHEREIN THE ALCOHOLS AND ACIDS EACH HAVE STRAIGHT CHAIN LENGTHS FROM 10TO 20 CARBON ATOMS.